Due to an increasing shortage of fresh water and the higher cost of available water, wasteful irrigation systems which were acceptable when water was “too cheap to meter” are being replaced by more complex but more water-saving systems. One of these is an array of fixed-position sprinklers, which irrigate more or less evenly a circular area or a sector of a circular area.
Sprinklers in general and pop-up sprinklers in particular were developed for applications where a fixed sprinkler is unacceptable due to it forming an obstruction during normal use of the area. Typically an underground pipe array distributes pressured water to a first group of sprinklers for a predetermined time, after which computer-controlled solenoid valves divert the water to a second group of sprinklers, and so on until all areas to be watered have received the quantity of water intended.
Due to the substantial commercial possibilities of this irrigation tool, much effort has been invested in the attempt to provide an improved unit. The large number of patents on this subject makes a full review of prior art impractical. The following US Patents reflect the situation at the time of writing:
U.S. Pat. Nos. 3,940,066, 3,957,205, 4,073,438, 4,220,283, 4,350,300, 4,351,477, 5,028,005, 5,871,156, 5,938,121, 6,478,237, 6,488,218, 6,457,656, 6,491,235, 6,530,531, 6,651,904, 6,808,127, 7,048,208, 7,097,116 and US Patent Application Nos. 2002/0179734, 2003/0071140, 2004/0046046 and 2006/0283976.
Many of the prior art sprinklers can irrigate only a circular area with the sprinkler being disposed in the center of the circle. To irrigate a rectangular or square area close spacing (often referred to as “head to head” overlapping) is needed. Some designs rely on diaphragms to seal joints between moving components. However these diaphragm seals have a short working life particularly when the water contains solid particles, requiring replacement of the diaphragm in an underground unit, which is a difficult and time-consuming task. Other designs suffer from quickly blocked nozzles using normal irrigation water and require fine filtering of the feed water with the inevitable loss of water pressure resulting. Other designs are too complex for economic manufacture. Yet further designs are susceptible to early clogging, jamming or breakage. Consequently no prior-art design has yet won wide acceptance.
It is therefore one of the objects of the present invention to obviate the disadvantages of prior art devices and to provide a sprinkler which can be adjusted to economically irrigate areas of almost any shape.
It is a further object of the present invention to achieve even distribution of water over the area being irrigated.
The present invention achieves the above objects by providing a sprinkler being adjustable for the even irrigation of a land area of regular or irregular shape, said sprinkler comprising:
a lower water inlet,
an upper member within upper housing suspended on a vertical axis within said lower water inlet housing, being free to revolve around a vertical axis and revolvably supporting;
at least one nozzle assembly having at least one water inlet and an outlet jet and being supported on a horizontal axis at least indirectly by said upper member within the said upper housing;
means for variably tilting said nozzle assembly(ies) in a horizontal axis in accordance with the changing angular position of said nozzle around the central vertical axis when water pressure is introduced into said lower water inlet housing; and
means for imparting a vertical axis rotary movement to the inner member part within said upper housing directly supporting said at least one nozzle assembly.
In a preferred embodiment of the present invention there is provided a pop-up sprinkler comprising:
a lower water inlet,
an upper housing attached to or being an integral part of, the said lower water inlet,
an upper member within the said upper housing is slidably suspended on a vertical axis in said guide means of said lower water inlet housing, said upper member within said upper housing being slidable between an upper, deployed position and a retracted lower zero-flow position, and at least a part of said upper member within said housing being free to revolve around a vertical axis when in said upper, operating position, and revolvably supporting;
at least one nozzle assembly having at least one water inlet and an outlet jet and being supported on a horizontal axis at least indirectly by said upper housing:
means for variably tilting said nozzle assembly(ies) in a horizontal axis in accordance, with the changing angular position of said nozzle around the central vertical axis when water pressure is introduced into said lower water inlet housing and when said upper member within said upper housing is in its upper deployed state; and
means for imparting a vertical axis rotary movement to the upper member within said upper directly supporting said at least one nozzle assembly.
In a preferred embodiment of the present invention there is provided a pop-up sprinkler wherein said means for variably tilting said nozzle assembly(ies) on a horizontal axis in accordance with the angular position on a vertical axis of said upper member within the upper housing comprises:
at least one thin flat ring cam made of a flexible material, held stationary by a non-revolving component of said sprinkler;
screw means for adjusting the height of any section of said flat ring cam; and
a cam follower unit arranged for contact around a face of said flat ring cam, linkage elements being provided to connect said cam follower unit to said nozzle assembly and thereby to impart a tilting movement thereto.
In another preferred embodiment of the present invention there is provided a pop-up sprinkler wherein said linkage elements is an L-shaped post holding at its lower end said cam follower provided with an upward-facing roller while said upper end carries slot elements to engage a pin projecting from said nozzle(s).
In a further preferred embodiment of the present invention there is provided a pop-up sprinkler wherein said nozzle(s) is/are mounted in a revolvable turret suspended in a non-revolving portion, at least one sleeve member, able to emerge out of said upper housing, said sleeve placed within the upper housing,
said turret provided at its lower end, flexible legs so when, it emerge (pop-up) through the upper housing said flexible legs located beneath the lower end of the sleeve member, lifting the sleeve.
In a further preferred embodiment of the present invention there is provided a pop-up sprinkler wherein there is provided a substantially vertical divider in said upper member (turret) within the upper housing to form a wet section and a dry section, wherein said at least at least one water inlet of said nozzle is disposed in said wet section while said nozzle outlet jet is disposed in said dry section.
In yet a further preferred embodiment of the present invention there is provided a pop-up sprinkler wherein pressurized water is fed to at least one of said nozzles through a tube serving as a pivot for tilting said nozzle, said water being fed through a tube, said water exiting said tube through an exit aperture in fluid communication with said central bore, said nozzle being provided with a water inlet aperture inside the pivot bore in contact with said tube, the inter-alignment of the two apertures varying during pivoting of said nozzle to provide a higher flow-rate when said nozzle outlet jet is tilted at an upward angle and a lower flow-rate when said outlet jet is directed nearer the horizontal plane.
In another preferred embodiment of the present invention there is provided pop-up sprinkler wherein said at least one thin flat ring cam is held in a plurality of radially spaced-apart track holders, said track holders being guided to allow free movement in a vertical plane, said track holders being provided with a vertical-plane screw thread to mate with an adjusting screw accessible for adjustment from a shoulder of said upper housing.
In most of the preferred embodiments of the present invention there is prodded a pop-up sprinkler wherein two nozzle assemblies are provided, a primary nozzle being configured for irrigating areas in the vicinity of the border of the area to be irrigated and a secondary nozzle assembly being arranged for irrigating areas nearer the sprinkler and to assist preserving an even precipitation rate upon the area confined inside the desired contour, and may have, in addition, at least one fixed unadjustable nozzle.
In order to reduce manufacturing expenses and using existing manufacturing lines and since it is realized that users of prior-art sprinklers may be reluctant to uproot the whole unit and replace it by a sprinkler according to the invention. To overcome this problem, the invention also provides for an upper part of the sprinkler which is adaptable to existing ready installed systems.
Yet further embodiments of the invention will be described hereinafter.
It will thus be realized that the novel device of the present invention serves to provide even coverage by automatically reducing the water flow accordingly when a section of the contour of the irrigated area is closer to the sprinkler. As an example, assuming that the speed of rotation on the vertical axis of the device is constant, it will be understood that for any fixed angle, e.g., 30° a sector between 8-10 meters distant from the sprinkler will be much larger than a sector between 4-6 meters away. Thus for even coverage the flow rate from the nozzle needs to be higher when a longer range area is being irrigated and lower for areas nearer the sprinkler. Also, many of the areas requiring irrigation are of a rectangular shape and not round, to serve this requirement the nozzle needs to be tilted further upwards in order to increase the sprinkler range in order to reach the corners of the area, and returned to its former position when the nozzle points in the direction of a side (particularly the longer side) of the rectangle. In the present invention this change of flow rate is achieved automatically in a simple manner, as will be seen in FIG. 6. It should be noted that, in addition, at least one fixed, unadjustable nozzle, in flow connection with the wet chamber, may be added for coverage of areas nearer the sprinkler.
The invention will now be described further with reference to a pop-up sprinkler and to the accompanying drawings, which represent by example preferred embodiments of the invention. Structural details are shown only as far as necessary for a fundamental understanding thereof. The described examples, together with the drawings, will make apparent to those skilled in the art how further forms of the invention may be realized. It should be noted that the same arrangement could be used for regular non pop-up sprinklers.